Adjuvant Radiotherapy May Benefit High-Risk RCC Patients
ATLANTA—Adjuvant radiotherapy may offer a high rate of local control with increased progression-free survival without significantly harming quality of life in patients with high-risk stage 3 renal cell carcinoma (RCC), data presented at the American Society for Radiation Oncology's 55th annual meeting.
“This is a controversial area,” said lead study investigator William Baquero, MD, an attending physician at the VIDT Centro Medico-21st Century Oncology, Buenos Aires, Argentina. “We don't have any treatment guidelines for adjuvant radiotherapy in these renal cell carcinoma patients. I was surprised that we had such good results in terms of clinical response.”
Dr. Baquero, who presented the study findings at the meeting, said the five-year overall survival (OS) rate for stage 3 RCC does not exceed 65%. In addition, he noted that in the presence of poor prognostic factors there tends to be an increased rate of local relapse affecting the quality of life in this patient population.
He and his colleagues studied 30 patients with stage 3 RCC who underwent radical nephrectomy and received adjuvant radiotherapy. The five-year local control rate was 93%, and only two patients relapsed in the retroperitoneum.
“Patients with bad prognostic factors should be offered this treatment,” Dr. Baquero told Renal & Urology News. “In general, these patients aren't offered postoperative radiotherapy but they should be.”
The mean time to local relapse was 67 months (range 36-91 months). The five-year OS rate was 80%, and the metastasis-free survival rate was 83%. Distant metastases developed in five patients (17%); the mean time to metastases was 68 months (range 9-91 months).
Patients received an external beam radiotherapy dose of 45-50 Gy to the nephrectomy bed, with 10-15 Gy Boost to micro/gross disease (1,8-2 Gy/fx).
The mean age of the patients was 57 years (range 36-73 years) and the mean follow-up was 71 months (range 14-91 months). Ninety percent of the patients had clear cell RCC, with infiltration of the capsule in 93% of cases. In addition, 53% had perinephric fat invasion and 20% had renal vein involvement.
The median radiation dose was 55Gy (50- 59.4Gy) and the reported toxicities included nausea (Grade 0-I) in 70% of the patients and Grade II-IV nausea in 30%. Vomiting (Grade 0-I) occurred in 80% and Grade II-IV vomiting occurred in 20%. Dr. Baquero said acute diarrhea (Grade 0-I) occurred in 96.6% and Grade II-IV in the remainder (3.3%), chronic gastrointestinal and hepatic toxicity were reported (Grade 0-I) 100%.
The study was limited by its retrospective design, Dr. Baquero noted. Prospective trials assessing new techniques and various fraction sizes of radiotherapy in selected patients may be warranted, he added.